Background: There was an outstanding improvement of survival in treatment of childhood acute lymphoblastic leukemia(ALL) after starting prophylatic therapy for central nervous system (CNS). But about 10% of ALL patients relapse at CNS and still it is the main cause of treatment failure. So, we analyzed the prognostic factors before and after isolated CNS relapse and tried to find the correlation with the prognosis.
Methods: The total number of childhood ALL patients who admitted to Department of Pediatrics, Severance Hospital from January, 1985 to July, 1995 were 257(age under 15 years). All the patients underwent BM aspiration and biopsy and classified according to FAB classification, CCG risk group classification and immunophenotype. Other clinical findings were included in the analysis.
Results: The patients wish CNS leukemia at diagnosis were 3, isolated CNS relapse in 25 patients, relapse combined with CNS in 9 patients, relapse without CNS involvement in 52 patients. Twenty five patients with isolated CNS relapse were analysized. There were higher relapse rate in intermediate and high risk group by CCG classification. When the initial WBC count was higher than 50×109/L, the survival duration was shorter(p<0.1). The survival duration was significantly shorter in intermediate and high risk group(p<0.1). The relapse before 24 months after diagnosis meant poor prognosis(p<0.05), but there were no correlation between prognosis and the methods of CNS prophylaxis.
Conclusion: There should be a re-evaluation of the methods of CNS prophylaxis. The patients with poor prognostic factors should be treated with more intensive chemotherapy and other factors like immunophenotype should be analysized more to make an accurate decision in treatment.